Monday, January 29, 2018

Issues of IoT

Image result for IoT

• Cyber security
• Privacy
• Software licensing
• Data use and ownership
• Regulation

IoT cyber security is a moving target. When a patch or fix is developed, it’s only a matter of time
before hackers find ways around it. In situations where IoT security is breached, who is liable? Is the
software maker liable if it doesn’t update its software? Who is liable if the software maker updates its software, but the user doesn’t
download the update? What happens if the software maker updates the software, but the user doesn’t know there’s an update?

Privacy and Laws
Privacy laws vary across countries. The Europeans are very protective
of privacy, and the US is less protective. Video rental habits are protected by federal laws,
not clear to of data generated by an implantable cardiac monitor is protected. Who owns datathat describes the quality and quantity of your heartbeats.

Governing the Internet of Things

Software Licensing—It’s Complicated
IoT requires software and hardware from multiple vendors.
Maintaining the software, hardware stack can be expensive.
In the IoT economy, there will be a handful of end-to-end solutions and a broad assortment of mash-ups.

Data Use and Ownership—Who Controls What?
who owns what data, where can it be sent, who is allowed to use it and how much if
it can be stored across the IoT landscape.

As the IoT becomes a more dominant force in our lives, the data it generates will become more valuable. Since the laws governing data ownership are ambiguous, rights associated with ownership are so unclear, look at who controls the use of data. It should be the consumer

Autonomous driving raises questions about data ownership and usage.
If a driverless car is involved in an accident, who is liable and who is allowed to review data relating to the accident? Will the manufacturer of the car want to see the data so it can lodge a suit against the developer who wrote the navigational software? Will network providers be required to share data with law enforcement agencies when autonomous vehicles collide?
Many questions but few answers yet .

Government regulation—or the lack of it
In the driverless car, precisely who is responsible in case of an accident—the owner of the car,
the company that made the car, or the company that wrote the software
guiding the car?

Wednesday, January 24, 2018

Subnetting in 5 minutes



192.168.1.7 is an IP in IPV4 standard
IPV4 networks have 32bits.
Each 8bit is a Network ID.
Each Network ID represent number between 0-255

There are 4 basic classes A , B C, D
The first ID or 8 bits is network class
0-127 - Class A
128 - 191 Class B
192 -  223 Class C
223 + Class D & E kept for research purpose

Class First Network ID Last Network ID
Class A 1.0.0.0 126.0.0.0
Class B 128.0.0.0 191.255.0.0
Class C 192.0.0.0 223.255.255.0

If we have a class C network
The first 3 numbers are network ID  192.168.1
The last number is host ID
First host id (0) is network id and last (255 broadcast id) not used
So in the network we have host ids from
192.168.1.1 - 192.168.1.254 we can have 254 hosts (computers or devices)
We do sub netting to separate network traffic , like partitioning  house.
we can make 2 networks each having 254/2 - 1*2  hosts
or make 4 networks having  254/4 - 1 *4

Every time we break the network the first and last host IDs are used as subnets network ID and broadcast ID.

Broadcast address used to send data to all hosts.
So they cant be used  as host IDs..
A disadvantage of subnetting is reducing of usable IPs in a network.

In order to tell the network how many computers we have in the subnet we use a subnet mask. Another number which tells how many subnet networks have been created.
When we have 254 computers in a class C network we use
255.255.255.0 as subnet mask so 192.168.1.1- 192.168.1.255 ips available to us.
When we break the network into two subnets. We have to put a boundry between them by changing the subnet mask.

Here subnet mask borrow one bit from host ID
so subnet mask becomes 255.255.255.128
The IP range of sub network A now is 192.168.1.1- 192.168.1.126
The IP range of sub network B now is 192.168.1.129- 192.168.1.253
The first and last IP of each subnet used for subnetworkid and broadcast address.

Check here
http://www.subnet-calculator.com/

 In detail http://ict.shilpa64.lk

Sunday, January 21, 2018

උසස් පෙළ ICT ආදර්ශ ප්‍රශ්න පත්‍රය

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